Significance of the Badenian petroleum source rocks from the Krndija Mt. (Pannonian Basin, Croatia)

Abstract

Discovery of petroleum source rocks at surface exposures of the Badenian deposits on the northern slopes of Krn dija Mt. is the first first record of petroleum source rocks at outcrop in the Croatian part of the Pannonnian basin. Rocks with increased organic matter content have the characteristics of prime source rocks. Positive hydrocarbon potential is the consequence of a favourable type of organic facies. Type II kerogen is of mostly marine algal origin, but with somewhat more pronounced terrigenic lipid content. Source rocks are in the immature, diagenetic period of thermal transformation. Genesis of these rocks is related to the reducing depositional environment in a mostly shallow sea, formed in protected lagoons during the Badenian period, which was reconstructed using palaeogeomorphological, palaeontological, petrographical and organogeochemical analyses. These new petrological data deserve attention as they highlight the need for additional geological-geophysical-geochemical research of the petroleum potential of the Badenian deposits in the broad area around Nasice. Discovery of petroleum source rocks at surface exposures of the Badenian deposits on northern slopes of the Krndija Mt. is the first record of petroleum source rocks on a surface outcrop in the Croatian part of the Pannonnian basin. Rocks with increased organic matter content have the characteristics of the prime source rocks. Positive hydrocarbon potential is the consequence of a favorable type of organic facies. Type II kerogen is of mostly marine algal origin, but with somewhat more pronounced terrigenic lipid content. Source rocks are in the immature, diagenetic period of thermal transformation. Genesis of these rocks is related to the reductive depositional environment in a mostly shallow sea, formed in protected lagoons during the Badenian period, which was reconstructed using palaeogeomorphological, paleontological, petrographical and organogeochemical analyses. This new petrological data deserve attention as it points out the need for additional geological-geophysical-geochemical research of the petroleum potential of the Badenian deposits in the broad area around Nasice.